Red fairway buoy on the Elbe with a container ship in the background
Under water

The Elbe: A river in the rhythm of the tides

There is a difference in water level of around 3.80 metres between high and low tide in the Port of Hamburg. We experience this tidal range on the River Elbe several times a day. This process moves large quantities of sand and mud, which are deposited in the navigation channel and in the port.

A staff gauge with the number 121 on a dolphin on the Elbe, in the background a bank with stones and trees
Level gauge for measuring the water level at the entrance to the Harburg harbour lock. In Hamburg, the difference between low tide and flood is currently 3.83 metres on average.

The Elbe is not a long, calm river here. On the contrary: the influence of the North Sea extends far inland here. From the mouth in Cuxhaven to the weir in Geesthacht, the Elbe is subject to the fluctuations of the tides. This 160-kilometre section is therefore also known as the Tidal Elbe. 

On this stretch, the river experiences a considerable difference between high and low water every six hours due to the tide, which is currently 3.83 metres in Hamburg. This means that the Elbe is constantly in motion here. When the ebb and flood tides change, large forces act under the surface of the water. The current causes a suction nozzle at the bottom and pulls natural components such as sand and mud with it - first in one direction, then in the other. However, these movements are not uniform, but are usually stronger from the sea side. The flood, which pushes the water inland, almost always has more force and pumps more silty material upstream than is washed back into the North Sea at low tide. This effect, which occurs in many estuaries around the world, is also known as "tidal pumping" and is all the stronger the less water flows down the Elbe, for example when the summers are very dry.

The stronger tidal current pumps more muddy material towards the harbour than is washed back towards the North Sea at low tide.
"Tidal pumping": In the tidal Elbe, the forces of ebb and flood act like a pump.

The tidal Elbe is therefore a dynamic system. Between the tides, when the current subsides a little, the particles sink to the bottom as so-called sediments. This creates new mudflats or elevations under water, which in turn influences the currents in the Elbe. Sediments are deposited particularly in places where the water flow velocity is already lower, such as in the harbour basin and side arms, causing these areas to silting up. Both the harbour basin and the navigation channel must therefore be regularly cleared of the accumulations of sand, mud and suspended matter, otherwise the Elbe will eventually no longer be passable for larger ships.

Aerial view of tidal flat and reed belt in the Elbe tidal flats at low tide, Elbe island Bishorster Sand
In the Elbe, suspended matter and sediments are transported by the currents, which then settle again in areas where the currents are calm.
Regular dredging is the only way to maintain the required water depths in Hamburg and the tidal Elbe. Just like in many other harbours around the world.

Two impressive videos by aquadot show the changing tides and floods from a bird's eye view.

We publish the exact parameters of the tides in Hamburg annually in the "hydrological information"

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FAQ on the tides of the Elbe in Hamburg

The most important questions and answers at a glance.

 

The Elbe in Hamburg is subject to the tides of the North Sea. The difference in height between high and low tide in the Port of Hamburg is currently around 3.80 metres, which means that the water level and current change significantly several times a day. This, for example, has an impact on the transport and displacement of suspended matter and sediment as well as shipping traffic.

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The influence of the tides extends from the estuary near Cuxhaven to the weir in Geesthacht. This approximately 160-kilometre-long section is also known as the Tidal Elbe or Elbe estuary.</p

 

 

Large quantities of sand and mud are moved by the ebb and flood tides. The stronger tidal current transports more sediment upstream towards the harbour than is carried back towards the North Sea at low tide ("tidal pumping").</p

 

 

In the tidal cycle, the current decreases at times (capsize points), causing suspended matter to settle as sediment - especially in current-calmed harbour basins and side arms. As a result these areas become silted up, which is why the fairway and harbour have to be dredged regularly.

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